SOME EFFECTS OF VARIOUS ENVIRONMENTAL TEMPERA¬ 
TURES UPON THE BLOOD OF DOGS 






BY 

FREDERICK B. FLINN 



From the United States Public Health Service and the Department of Physiology, 
Columbia University, New York 


Submitted in partial fulfillment of the requirements for the degree of Doctor 
of Philosophy, in the Faculty of Pure Science 


I 




Reprinted from The American Journal of Physiology 
Vol. LXVI, No. 1, September, 1923 






SOME EFFECTS OF VARIOUS ENVIRONMENTAL TEMPERA¬ 
TURES UPON THE BLOOD OF DOGS 


BY 

FREDERICK B. FLINN 

* 


From the Uniled States Public Health Service and the Department of Physiology, 
Columbia University, New York 


Submitted in partial fulfillment of the requirements for the degree of Doctor 
of Philosophy, in the Faculty of Pure Science 



Reprinted from The American Journal of Physiology 
Vol. LXVI, No. 1, September, 1923 



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SOME EFFECTS OF VARIOUS ENVIRONMENTAL TEMPER¬ 
ATURES UPON THE BLOOD OF DOGS 1 

FREDERICK B. FLINN 

From the United States Public Health Service and the Department of Physiology, 
Columbia University, New York 

Received for publication June 13, 1923 

Our object in undertaking this research was to acquire a more 
intimate knowledge of the specific effects of high environmental 
temperatures upon certain individual organs and tissues of the body, 
so that general effects as observed among furnace workers could be 
interpreted more accurately than has heretofore been possible. 

Unfortunately, there are no animals in common use in the labo¬ 
ratory which are wholly suitable for such a study. Of the domestic 
animals the horse is perhaps to be preferred because of the greater 
similarity of its heat-controlling apparatus to that of man, but in¬ 
asmuch as facilities for handling animals of this size were not avail¬ 
able we were compelled to consider the smaller animals. Of these, 
dogs were selected as being the most tractable and, all things con¬ 
sidered, the best adapted for the work which we planned to do. In 
making this selection it was frankly recognized that the dogs have 
developed a method of cooling the body by the evaporation of water 
which is strikingly different from that which obtains in the horse and 
man. However, in spite of this dissimilarity and its possible effects 
upon the gases of the blood, our results seem to indicate that any 
differences are quantitative and that the qualitative changes in gas 
content which result from exposure to high temperatures are the same 
for the two forms. Aside from this theoretical objection the dogs 
proved to be as nearly ideal as could be hoped for. 

We have centered our attention on a single tissue—the blood. 
This tissue was chosen because of the rapidity and accuracy with 
which it reflects changes taking place throughout the organism, and 
because it is the only tissue which may be sampled at intervals and 
still leave the animal in what may be presumed to be an approximately 
normal condition. The blood was analyzed for oxygen content and 
capacity, carbon dioxide content and capacity, sugar and total solids, 

i Approved for publication by the Surgeon General. 

191 


192 


FREDERICK B. FLIXX 


all of which were determined as a matter of routine. In a few cases 
the iron of the blood was determined as a control on the oxygen 
capacity. In a second series the hydrogen-ion concentration and the 
carbon dioxide content of the plasma were determined as routine, 
while an occasional determination of the lactic acid in the blood was 
made. 

In presenting the data which we have accumulated, we are aware 
that various investigators, from the time of Claude Bernard on, have 
reported observations on the blood of animals which were exposed to 
high temperatures, but it seems to us that these results are not only 
fragmentary but in some cases of such doubtful accuracy that a 
clear-cut interpretation is practically impossible. The inaccuracies, 
where they exist, are due not only to faulty chemical technic but 
frequently to an abnormal condition of the animals. For example, 
many of them were subjected to anesthesia, which disturbs not only 
the heat-regulating mechanism but also the general metabolism of 
the subject. Furthermore, these observations were made at various 
times upon various species of animals, while in the present research 
we have endeavored to correlate as many data and data of as many 
different types as is practical on a given series of individuals of a 
single species. 

In addition to the previously mentioned observations on the 
blood, we have recorded the rectal temperature and -the body weight 
whenever a sample of blood was drawn, and in certain of the experi¬ 
ments even more frequently. 

Methods: I. Chemical, a. The blood gases. The carbon dioxide 
content and capacity of the blood were determined by the methods 
of Van Slyke (1). The oxygen content and capacity were deter¬ 
mined by the method of Van Sh’ke and Stadie (2), but we found it 
necessary to add three or four drops more of the potassium ferri- 
cyanide solution than is recommended by these authors, possibly 
because our ferricyanide was the product of a different manufacturer. 

All of the results reported were obtained with the old form of the 
Van Slyke apparatus, having the short stem. This apparatus was 
checked against the newer form having the longer stem and the water 
jacket and we did not feel that the differences in the results were 
sufficient to warrant the extra time required by the latter apparatus; 
for this would have necessitated an additional observer and, in our 
opinion, the differences due to personal equation would have more 
than offset the greater precision of the later apparatus. 

b. The sugar of the blood. MacLean’s method for 1 cc. of blood (3), 
as modified by Hastings and Hopping (4), was used throughout the 
work. 


EFFECT OF TEMPERATURE UPON BLOOD OF DOG 


193 


c. The total iron of the blood was occasionally determined as a 
means of controlling the oxygen determinations, using the method 
published by Brown (5). In this work we found that the colorim¬ 
eter gave a more satisfactory means of comparing the colors than 
did the method described by the author. 

d. The lactic acid was determined by the method which we have 
described elsewhere (6) except that the filtrate was extracted with 
ether and the determination made on the ether extract instead of on 
the filtrate directly. This was done upon the suggestion of Dr. 
Isidor Greenwald, in order to avoid the disturbing influence of the 
sugar of the blood. It is recognized that this method is not specific 
for lactic acid but since we were unable to find indications of an 
increase we feel that it is sufficient to justify the conclusions which 
we have drawn. 

f. The total solids were determined by drying 1 cc. of blood to 
constant weight in an electric oven at 110°C. This was done in 
duplicate in silica crucibles. 

g. The hydrogen-ion concentration was determined by the colori¬ 
metric method described by Cullen (7). The phosphate solutions 
which were used as standards of comparison were checked by means 
of the potentiometer. 

II. Physical, a. The temperature chamber. The chamber in which 
the animals were exposed to the various environmental conditions was 
constructed of two layers of beaver board separated by a 4-inch air 
space. The chamber contained three windows, one at one end, 
another on one side and a third on the top. These windows were 
each about 2 feet square, and consisted of two sheets of glass with a 
2-inch air space between them. A gas stove was placed inside at 
one end, under the window; at the opposite end there was a single 
wooden door lined with beaver board. The inside dimensions of the 
chamber were 4 feet in width by 7 feet each in length and height. 

The method of heating, of heat control and of ventilation was 
that described by Hastings (8), and it has proven very satisfactory. 
The gas flow was controlled by a Roux regulator. A 6-inch electric 
fan was installed to overcome stratification and pockets in addition 
to the use of convection currents as recommended by Hastings. 
Thermometers placed in various parts of the chamber showed no 
stratification or variations in temperature greater than one-half of 
one degree Centigrade, while the temperature of the chamber as a 
whole did not vary more than one degree throughout the day. 

6. The relative humidity within the chamber was determined by 
means of a sling psychrometer. 



194 


FREDERICK B. FLINN 


c. The body temperature was taken by an ordinary certified 1-min¬ 
ute clinical thermometer inserted in the rectum. The thermometer 
was left in place for at least minutes. 

d. The respiratory rate was counted by means of a Fitz pneumo¬ 
graph writing on a smoked drum through a Marey tambour. This 
technic was made necessary by the extremely high rates of respiration 
encountered at the higher temperatures. 

III. Biological. All of the dogs used in these experiments were 
adult, short-haired mongrels, varying in weight from 10 to 15 kilo¬ 
grams. They were kept, when not actually in use for the experiments, 
in a kennel on the roof, and were maintained in a healthy condition 
throughout. It is needless to say that they were used exclusively 
for the purpose of the research here reported. 

Their diet consisted of bread and cooked meat in an amount at 
least sufficient to maintain their weight. As a matter of fact, most 
of them gained in weight during the course of the experiments. They 
received no food during the period of 18 hours preceding each experi¬ 
ment. No food or water was permitted during the period of the 
experiments. 

It was our practice to bring the dog which was to be used for an 
experiment to the laboratory at least half an hour before actually 
beginning the work, in order that he might become quiet and some¬ 
what accustomed to conditions and to the personnel of the laboratory 
before the initial sample of blood was drawn. A rest period of at 
least two weeks was permitted each dog between experiments to allow 
recovery from any deleterious effects caused by the high temperature 
or from the hemorrhage attendant upon the experiment. 

During the exposure in the heat chamber the animals ..were either 
confined in a cage or tied, so that while they had a certain amount 
of freedom they could not come in contact with the stove or otherwise 
injure themselves or the apparatus. At the lower temperatures they 
usually rested quietly or slept unless disturbed for purposes of obser¬ 
vation. At 45° and 50°C. they were somewhat restive during the 
first few minutes of the exposure but later became quiet. 

All of the blood samples were drawn from the jugular vein by 
venepuncture, in no case was venesection practiced. 

For the convenience of the reader the results are presented in the 
form of graphs. These have been plotted from the means calculated 
from the various values obtained at the end of each interval and at 
each temperature. In order to obtain some idea of the mean average 
condition of the animals at the beginning of the experiments, the 
means and the mean standard deviations for all of the initial values 
of the several determinations were calculated. These mean initial 


EFFECT OF TEMPERATURE UPON BLOOD OF DOG 195 

values we have used as a base with which to compare the effects of 
the experimental procedures. This was done by adding algebraically 
to each of the means of an experimental series an amount sufficient 
to make the initial value of that series equal to the mean of all the 
corresponding initial determinations. Exactly what was done will 
be made clear by reference to table 1. In this table are shown the 
means obtained for the initial determinations and those for a single 


TABLE 1 

To illustrate the method used in tabulation and the derivation of the data used in 

plotting the curves 



BODY 

WEIGHT 

RECTAL 

TEM¬ 

PERA¬ 

TURE 

PER 100 CC. OF BLOOD 

C0 2 

con¬ 

tent 

CO 2 

ca¬ 

pacity 

O 2 

con¬ 

tent 

O 2 

ca¬ 

pacity 

Glu¬ 

cose 

Total 

solids 

Initial values, 47 observations 

Mean values. 

Mean standard deviation. 

Kg 

°c. 

38.7 

CC. 

46.7 

±4.8 

CC. 

62.5 

±4.9 

CC. 

17.7 

±3.4 

CC. 

25.1 

±3.1 

mum. 

91 

±11 

mum. 

21.7 

±2.1 


Chamber temperature 20°C. Relative humidity 0.46; 12 observations 


Initial mean.. 

14.8 

38.9 

45.2 

67.0 

18.4 

25.3 

92 

22.2 

Correction added. 


-0.2 

1.5 

-4.5 

-0.7 

-0.2 

-1 

-0.5 

Modified mean. 


38.7 

46.7 

62.5 

17.7 

25.1 

91 

21.7 

Mean standard deviation. 



±5.4 

±3.3 

±3.0 

±3.5 

±12 

±2.0 

2nd hour, mean. 

14.8 

39.0 

45.8 

66.9 

19.0 

25.7 

87 

22.4 

Modified mean. 


38.6 

47.3 

62.4 

18.3 

25.5 

86 

21.9 

Mean standard deviation. 



±5.6 

±3.3 

±3.0 

±3.9 

±17 

±1.8 

4th hour, mean. 

14.7 

38.2 

46.0 

67.7 

18.8 

25.6 

85 

22.8 

Modified mean. 


38.0 

47.5 

63.1 

18.1 

25.4 

84 

22.3 

Mean standard deviation. 



±5.3 

±3.7 

±3.1 

±3.0 

±16 

±2.5 

6th hour, mean. 

14.7 

38.3 

46.0 

67.9 

18.8 

25.5 

83 

22.3 

Modified mean. 


38.1 

47.5 

63.4 

18.1 

25.3 

82 

21.8 

Mean standard deviation. 



±5.2 

±3.6 

±3.4 

±3.4 

±15 

±1.9 


temperature—20°. Together with the means are shown the correc¬ 
tion which was added and the modified mean so obtained. This 
last was used in all cases in plotting the curves shown, (cf. Scott 
and Ford (9).) 

The formula used in calculating the mean standard deviation was: 


a 


ilid) 

\N - 

V N 


2 

I 


THE AMERICAN JOURNAL OF PHYSIOLOGY, VOL. 66, NO. 1 




















































196 


FREDERICK B. FLINN 


where a = the mean standard deviation; d = the arithmetical differ¬ 
ence between the individual determinations and the mean for the 
series, and N the number of observation. 

It is planned to publish shortly the complete data obtained in this 
research together with additional material as a bulletin of the United 
States Public Health Service. It is hoped that those interested in 
the detailed results will make use of this publication. 


TABLE 2 

To show Ihe number of observations made and the individual dogs used in the first 
series, embracing determinations of oxygen content and capacity, carbon 
dioxide content and capacity, blood sugar and total solids 


CONDITIONS 


OBSERVATIONS ON DOG 


TOTAL 

Temperature 

Mean 

relative 

E 

H 

J 

M 

P 

Q 

OBSERVA¬ 

TIONS 

humidity 







°C. 









Initial 


7 

4 

5 

10 

10 

10 

46 

20 

46 

2 

2 

2 

2 

2 

2 

12 

30 

43 

2 

2 

2 

2 

2 

2 

12 

40 

39 

2 

0 

1 

2 

2 

2 

9 

45 

35 

1 

0 

0 

2 

2 

2 

7 

50 

28 

0 

0 

0 

2 

2 

2 

6 


TABLE 3 

To show the number of observations made and the individual dogs used in the second 
series, embracing determinations of the concentration of hydrogen ion and 
carbon dioxide content of the oxalated plasma 


TEMPERATURE 

OBSERVATIONS ON DOG 

TOTAL 

OBSERVATIONS 

M 

P 

S 

T 

°c. 

• 





20 

1 

1 

1 

1 

4 

30 

1 

1 

1 

1 

4 

40 

1 

1 

1 

1 

4 

45 

2 

2 

2 

2 

8 

50 

2 

2 

2 

2 

8 


Experimental results and discussion. The total number of 
experiments which were carried out together with the experimental 
conditions to which the animals were subjected as well as the individ¬ 
ual dogs which served as subjects are indicated in tables 2 and 3. 

I. The effects of various environmental temperatures upon the body 
temperature. The changes in the body temperature during exposure 
to the several conditions studied are shown graphically in figure 1. 





































Percent Dcgr«« CenUgfade 


EFFECT OF TEMPERATURE UPON BLOOD OF DOG 


197 


The mean body temperature for forty-seven initial observations was 
38.7°C. It was found that the body temperature fell slightly for a 
time and then remained at a fairly constant level for the remainder 
of the period of observation. This agrees with the results reported 
by the New York State Commission of Ventilation for men when 
they were subjected to similar conditions (10). 

At environmental temperatures of 30° the history for the dogs 
was much the same as for 20° except that the fall in body tempera¬ 
ture was not quite so marked. The New York State Commission 



Fig. 1 . Curves to show the relation between various environmental tempera¬ 
tures and the temperature of the body and the total solids of the blood of dogs. 


of Ventilation reported a slight rise of body temperature in men when 
they were exposed to an environmental temperature of 30°, though 
in their case the humidity was 80 per cent, much higher than in any 
of our experiments. The explanation of this behavior is not clear 
to us although it may possibly be related to the normal diurnal 
variations in the body temperature as our observations and those 
of the Commission were begun in the morning and continued for 
some time through the day. Or again it may be related to the 
decreased muscular activity which accompanies confinement in the 
chamber and to the fact that no food was taken during the course of 
the observations. This latter interpretation seems the more probable 




















198 


FREDERICK B. FLINN 


in view of the fact that the diurnal curves usually shown are highest 
in the late afternoon and hence vary in the sense opposite to that 
observed by us. 

A consideration of the work of Rubner (11) is of interest at this 
point, for he has shown that at 20°C. the dog manifests no increase 
in the rate of metabolism, and that this condition of unchanging 
metabolism persists while the environmental temperature is raised to 
at least 30°. He has further demonstrated that in the fasting animal 
the minimum energy release occurs at temperatures of from 30° to 
35°C. This might be called the basal energy requirement, or the 
minimum energy release compatible with mammalian life. 

When the temperature of the chamber is raised to 40°, the response 
is quite different. Here we find a rise of 1 degree in body temperature 
during the six-hour period of observation, and as a rise was apparent 
at the end of the first hour of exposure there was no evidence of an 
initial fall as observed in the two previous cases. The temperature 
remains constant during the middle period, the rise being confined 
to the first and last two-hour periods. Whether or not this is of 
significance we are not prepared to say. 

At temperatures of 45° and 50° a very marked rise of the rectal 
temperature was noted, which apparently began at once. In fact 
this rise was so sharp that at the end of one hour the body temperature 
had risen to such a point that it was not deemed safe to continue the 
experiments at these temperatures for a longer time. On removal 
of the animal from the chamber the body temperature rapidly fell 
and two hours after removal the body temperature was subnormal, or 
about 36°. This subnormal temperature reminds one of the con¬ 
ditions in certain stages of heat stroke in man. 

It will be noted that the body temperature is the same whether 
the animal had been exposed to an environmental temperature of 
45° or 50°. This remarkable fact of a similar physiological response 
to conditions of different severity was noted in some of the other 
factors studied it being especially marked for those having to do with 
the carbon dioxide. The organism seems to yield with increasing 
rapidity as the strain impressed upon it becomes more severe, until 
a certain limit is reached at which point great resistance is inter¬ 
posed by the organism against any further change. If the strain 
is increased so that the organism is pushed beyond this point, it will 
recover with great difficulty, if at all, unless external aid is given. 
This same type of physiological limitation was noticed by Henderson 
and Haggard (12) during their work on low levels of carbon dioxide 
and alkali reserve induced by ether. It was also noticed by Britton 
in his studies on cooling. In order to lower the temperature of his 


EFFECT OF TEMPERATURE UPON BLOOD OF DOG 


199 


animals below what might be called the critical point he found it 
necessary to subject them to anesthesia until it had been passed, 
after which the anesthesia was no longer necessary and the body tem¬ 
perature continued to fall so long as the animal was exposed to an 
environmental temperature lower than the body temperature. 

II. The effects of various environmental temperatures upon the 
oxygen content and upon the amount of hemoglobin in the blood. 
Considering first the oxygen capacity (hemoglobin) we find very 
little variation throughout the series. In fact, all of the mean values 
are within the limits of the mean standard deviations of the 20° 
series and so from a purely statistical standpoint are without signifi¬ 
cance. The direction of the slight variations which do occur fits 
so nicely with other circumstances, however, that one hesitates to 
dismiss them without further discussion. (Fig. 2.) 

The changes noted at 20° and 30°, if not entirely fortuitous, may 
be an example of the diurnal changes studied for man and the goat 
by Dreyer, Bazett and Pierce (14). At temperatures of 40° and 
above there is a slight tendency for the oxygen capacity to increase, 
this tendency becoming somewhat more marked as the environ¬ 
mental temperature rises. This increase is paralleled by an increase 
in the total solids, and we have related it simply to an increase in the 
concentration of the blood due to the excessive evaporation of water, 
accompanied by an inability of the water reservoirs to supply water 
at a rate sufficient to meet the demand made upon them at these high 
temperatures. 

The fact that there was no increase in the oxygen capacity during 
the first two-hour period of exposure to a temperature of 40° would 
seem to bear out this interpretation. It might fairly be assumed that 
at this temperature the loss would not be so rapid but that sufficient 
time would be permitted for equilibration and that there had not yet 
occurred so great a loss that the available store of water had become 
seriously depleted. The later rise, then, was probably due to an 
actual depletion of the available water below a limit where the 
original concentration of the blood could be maintained. 

At 45° and 50° it may be presumed that while the actual quantity 
of water which has been lost from the tissues during the first hour of 
exposure is not of itself serious, the rate of loss of water from the 
blood is so rapid that the organism is unable to maintain the original 
concentration of the blood. This interpretation is further supported 
by the rapid return of the oxygen capacity and of the total solids to 
their original level during the first two hours after the animal was 
removed from the chamber. 




CC of gas per 100 C.C BlooA Verc-ervt 


200 


FREDERICK B. FLINN 


A very slight fall is noted in the oxygen capacity of the animals 
exposed to 30°. A comparison of this fall with the mean standard 
deviation of the 20° series, however, indicates that it is too small to 
be of significance from the standpoint of statistics. Some biological 
considerations, on the contrary, seem to show that it may have some 
importance; but this evidence is not sufficient to warrant discussion 
at the present time. 

There is a fairly marked fall in the oxygen content of the venous 
blood of animals exposed to a temperature of 30° as compared with 



Fig. 2. Curves to show the effects of various environmental temperatures upon 
the oxygen capacity, oxygen content and the percentage of oxygen saturation of 
the venous blood of dogs. 


that of animals exposed to a temperature of 20°. This drop we 
believe to be a reflection of the manner in which the animals respond 
to the two temperatures. At 30° and the humidities at which we 
were working, there seems to be nearly an equilibrium between the 
heat generated in the basal metabolism and the heat lost to the 
environment. (Cf. Voit (15).) The animals are quick to take 
advantage of this and stretch themselves out and take life easily. 
Hyperpnea has not yet become necessary to keep the temperature 
of the body down. All muscular movements, and consequently heat 
generation, are at a minimum. The net result is a considerably 


























EFFECT OF TEMPERATURE UPON BLOOD OF DOG 


201 


reduced aeration of the blood, as well as a reduced circulation and 
consequently a reduced oxygen content, especially of the venous 
blood. 

At 40° there is a considerable increase in the rate of respiration, 
and correlated with this, a rather marked increase in the oxygen 
content of the blood. The rate of increase in the oxygen content is 
slightly greater at 45° and 50°, respectively, than it is at 40°, but the 
increased rates are not nearly so great as might be expected when 
one compares them with that occurring between 30° and 40°. There 
are at least two factors concerned in this: First, while the rate of 
respiration continues to increase as the environmental temperature 
continues to rise it becomes progressively shallower (fig. 3), so that 
while the efficiency of the respiratory apparatus as a cooling mechan¬ 
ism may rise because of the increased passage of air over the mem¬ 
branes of the mouth and throat and a consequent increase in the 
vaporization of water, its efficiency as a means of aerating the blood 
does not increase in anything like the same ratio, if at all. Second, 
with the increased body temperature which accompanies exposure 
to these high environmental temperatures the rate of metabolism 
is increased and this would of course be reflected in a decreased 
oxygen content of the venous blood provided that there was not at 
the same time a considerable increase in the amount of oxygen carried 
in the arterial blood, which from the evidence just discussed, is 
probably not the case. The curves showing the percentage of satur¬ 
ation (fig. 2) are very satisfactorily explained on this hypothesis. 

III. The effects of various environmental temperatures upon the 
carbon dioxide content and upon the alkali reserve of the blood. There 
is no change in the carbon dioxide capacity of the blood during an 
exposure of six hours to a temperature of 20° or of 30°, as is shown 
in figure 4, where it will be seen that the two curves are identical 
within the limits of the mean standard deviation and that both are 
horizontal. 

When the environmental temperature is raised to 40° there is a 
fairly rapid fall during the first four hours and a somewhat slower 
fall during the remaining two hours. At 45° and 50° there is a very 
rapid depletion of the alkali reserve as shown by the carbon dioxide 
capacity, this depletion being almost identical in degree for the two 
temperatures. This is a very good illustration of the critical point 
previously mentioned in the discussion of body temperature. We 
believe that the changes noted result directly from the equilibration 
necessitated by the washing out of the carbon dioxide which, in turn, 
is caused by the hyperpnea due to the high temperatures—a hyperp- 
nea which may even become dyspnea if the exposure is long continued. 



202 


FREDERICK B. FLINN 


The carbon dioxide content (fig. 5) gives a similar picture, except 
that here a slight rise is noted in the animals exposed to an environ¬ 
mental temperature of 30°. This probably results from the same 
cause as the corresponding slight depression of the oxygen content 



Fig. 3. Pneumographic tracings to show the relative rate and depth of respira¬ 
tion of dogs subjected to environmental temperatures of 20° and 50°C. 


which was noted for the same condition, i.e., a small decrease in the 
rate of metabolism, which would be, under these conditions, at its 
lowest ebb as shown by Rubner and others. This decreased metab- 











100 CC B\o<A 


EFFECT OF TEMPERATURE UPON BLOOD OF DOG 


203 


olism would result in a slight lowering of the rates of respiration and 
circulation. 

IV. The effects of various environmental temperatures upon the 
hydrogen-ion content of the plasma. The hydrogen-ion concentration 



Fig. 4. Curves to show the effects of various environmental temperatures upon 
the alkali reserve of the blood of dogs as determined by the carbon dioxide 
capacity. 



Fig. 5. Curves to show the effects of various environmental temperatures upon 
the carbon dioxide content of the venous blood of dogs. 


expressed as pH remains constant for at least six hours when the 
animals are exposed to temperatures of 20° or 30° (table 4) and falls 
within the normal acid-base balance, or area 5 of the Van Slyke 

























































204 


FREDERICK B. FLINN 


chart (16). At 40° with an increased rate of respiration and the 
resultant fall in the carbon dioxide content and the alkali reserve, 
we find that the blood index has passed from area 5 to area 6 of the 
Van Slyke chart, or into the region of compensated carbon dioxide 
deficit. The alkali reserve likewise falls thus preventing an abnormal 
alkalinity. As the strain becomes greater with environmental tem¬ 
peratures of 45° and 50°, the pH increases from the normal of 7.55 to 
7.79 and to 7.84 for the two temperatures respectively. The carbon 
dioxide of the plasma has dropped to 29.9 and to 26.3 volumes per 
cent and the plasma index has passed into area 2 or 3 of the Van Slyke 
chart or into the region of uncompensated carbon dioxide deficit as 
the result of an excessive loss of carbon dioxide. This loss of carbon 


TABLE 4 

To show the effect of various environmental temperatures upon the concentration of 
the hydrogen ion and carbon dioxide content of the plasma 


TEMPERATURE 
*OF CHAMBER 

BEFORE EXPOSURES 

AFTER ONE HOUR 
EXPOSURE 

AFTER SIX HOURS 
EXPOSURE 

pH 

COi content 

pH 

COs content 

pH 

CO, content 

°c. 







20 

7.57 

52.4 

7.57 

52.4 

7.57 

55.4 

40 

7.57 

52.4 

7.56 

46.6 

7.56 

39.5 

45 

7.57 

52.4 

7.79 

29.89 



50 

7.57 

52.4 

7.83 

26.3 




dioxide was induced by an increase of the respiratory rate which was 
evidently brought about by some stimulus other than an increased 
concentration of the hydrogen-ion. The same condition, also accom¬ 
panied by hyperpnea, has been observed by Bazett and Haldane (17) 
in man when immersed in warm baths. 

Kahn (18) and Barbour (19) are of the opinion that the mechanism 
causing the increased rate of respiration is the increased temperature 
of the blood, that is, it is the direct result of the increased body temper¬ 
ature. It is known that cellular activities in general increase, within 
limits, with the temperature and there is no apparent reason for ex¬ 
cepting the respiratory center from this category. It was at first 
thought that the stimulus might be due to a local accumulation of 
hydrogen-ion within the cells of the respiratory center itself, which 
might occur as a part of a general tissue anoxemia depending upon the 
increased stability of the oxyhemoglobin at low carbon dioxide concen¬ 
trations. (Cf. Bohr (20).) If such an anoxemia should in truth exist 
one would expect to find it indicated by an accumulation of lactic acid 
in the blood, but a careful search has failed to show the slightest increase 
















EFFECT OF TEMPERATURE UPON BLOOD OF DOG 


205 


of this acid in the blood of animals exposed to high temperatures, over 
the amount occurring under ordinary conditions. It is difficult for us 
to imagine a significant acidosis occurring in the tissues without its 
being mirrored in the blood stream. 

Our work does not permit us to accept the suggestion of Hill and 
Flack (21) and of Mayer (22) that fatal termination from over-heating 
is due to an accumulation of acid. We found a decreased rather than 
an increased hydrogen-ion concentration in the plasma of all of our 
animals which recovered from exposure to severe conditions and in 
none did we find any indication of increased lactic acid. From two 
animals, Q and R, which died shortly after removal from the chamber 
after having been exposed to rather severe conditions, blood was 
drawn only a few minutes before death. The mean values obtained 
were: 


Oxygen content. 5.9 Carbon dioxide content.30.5 

Oxygen capacity.23.6 Carbon dioxide capacity_ 36.7 


Hydrogen-ion determinations were not made, but from the Henderson 
nomogram (23) the pH may be presumed to have been about 7.4, which 
would not indicate acidosis. (Compare Henderson (24).) 

Since the respiratory efforts gave every indication of the passage of 
at least a normal volume of air up to the time that the samples were 
taken we have interpreted the changes which occurred as indicating 
circulatory rather than respiratory failure, this having been induced by 
the overload thrown on the circulatory mechanism in the effort to keep 
the body temperature down. 

V. The relation between the concentration of the sugar in the blood and 
the temperature of the environment. The changes in the concentration 
of the sugar in the blood (fig. 6) are rather hard to explain in a manner 
which is consistent for all of the conditions studied. At 20° there is a 
fairly uniform fall throughout the six-hour period of observation. This 
is in entire agreement with the observation of Scott and Hastings (25) 
and can hardly be related to the ingestion of food since sufficient time 
was allowed for this factor to become constant before the first sample 
was drawn. The only explanation which occurs to us is that the animals 
were becoming progressively quieter as the experiments proceeded and 
consequently were mobilizing less and less sugar. Whether such a 
decrease in the rate of mobilization of sugar is the direct result of 
lessened excitement, or whether it is due to the operation of an unknown 
factor which tends to equilibrate the concentration of sugar in the blood 
with the metabolic requirements of the organism for sugar, is a matter 
which we are unable to discuss at present. Aside from this factor 
which may be assumed, for the time being, to have been constant 




206 


FREDERICK B. FLINN 


throughout the research, it is to be noted that when the corresponding 
periods of the different series are compared a rough agreement between 
the concentration of the sugar in the blood and the body temperature 
is noted. The 45° series forms an exception to the rule, however, for 
at this environmental temperature the body temperature is almost 
identical with that which occurs when the animals are exposed to a tem¬ 
perature of 50°; while the concentration of sugar occupies a position 
midway between that found at 40° and that at 50°. This rise in the 
blood sugar is then not exclusively dependent upon the body tempera¬ 
ture but seems also to be associated with the environmental temperature 



Fig. 6. Curves to show the effects of various environmental temperatures upon 
the concentration of glucose in the venous blood of dogs. 


in a more direct manner. It is apparently not dependent upon any 
emotional disturbances resulting from the exposure to the higher tem¬ 
peratures. We hope to be able to give further evidence regarding this 
phase in a later paper. Lupine (26) attributes the hyperglycemia 
which is occasionally present in fever to an irritation of the fourth 
ventricle by the fever toxins. The increase in the concentration of 
sugar which Freund and Marchand (27) report in fever is only of such 
a degree that it may be accounted for by changes in the concentration 
of the blood. We are not, however, able to explain our results in this 
manner since we found the increase in the sugar to exceed that of the 
total solids; in one case there was an increase in the sugar of 100 per cent 
while at the same time the total solids increased only 25 per cent. 
























EFFECT OF TEMPERATURE UPON BLOOD OF DOG 


207 


VI. The relation between the total solids of the blood and the environ¬ 
mental temperature. The total solids of the blood tend to increase as the 
environmental temperature rises and we have been unable to observe 
the dilution mentioned by Barbour (28) in the report of his experiments 
with hot and cold baths. Our results seem to be more in line with the 
results which he obtained in coli fever (29). There is no doubt some 
mechanism by which the total blood volume is regulated, and our 
results should be considered as indicating some interference with the 
activity of this mechanism. At high temperatures the rate of replace¬ 
ment of water cannot keep pace with the rate of its loss and a certain 
amount of concentration results. There is, however, a fairly large 
factor of safety for it is not until the concentration of the blood ap¬ 
proaches 25 per cent that pathological symptoms occur from this cause. 

SUMMARY 

1. During an exposure of six hours to an environmental temperature 
of 20° or of 30° there was a drop in body temperature, probably due to 
a decrease of muscular activity. At 40° there was an increase of 1 
degree in body temperature without an initial drop. At 45° and 
50° the body temperature rose within an hour to such a height that it 
was deemed unsafe to continue the experiments at these temperatures 
for a longer time. 

2. The oxygen capacity of the blood showed no change during an 
exposure to the different temperatures that cannot be accounted for by 
the diurnal changes in the hemoglobin or by the concentration of the 
blood due to the excessive evaporation of water. 

3. The oxygen content of the blood remains unchanged at 20°, but 
shows a drop at 30° which is probably associated with the low rate of 
metabolism at this temperature. At 45° and 50° there is a slight in¬ 
crease in the oxygen content due to the increased aeration of the blood 
at these temperatures, but this increase is not in direct proportion to 
the increased passage of air over the membranes of the mouth and 
throat. 

4. At temperatures of 20° and 30° the carbon dioxide capacity of the 
blood remains unchanged, while at 40° there is a sharp fall during the 
first four hours followed by a slower fall during the next two hours. 
At temperatures of 45° and 50° there is a rapid depletion of the carbon 
dioxide capacity from the beginning, which is almost identical for these 
two temperatures. 

5. The carbon dioxide content follows the capacity except that at 
30° there is a slight rise for the same reason that the oxygen content 
falls. 


208 


FREDERICK B. FLINN 


6. The hydrogen-ion content of the plasma remains unchanged during 
an exposure of the animal to temperatures of 20°, 30° and 40° for six 
hours, but decreases at temperatures of 45° and 50° due to the excessive 
pulmonary ventilation at these temperatures with the consequent 
washing out of the carbon dioxide and without a compensatory loss of 
alkali from the blood. 

7. The concentration of blood sugar falls during an exposure to tem¬ 
peratures of 20° and 30°. This fall is probably associated with inac¬ 
tivity of the animal during the course of the experiment. At 40° it 
falls during the first two hours, to increase during the following four 
hours. At 45° no change was noted during an hour’s exposure while 
at 50° there was a sharp rise during this time. 

8. The blood solids at 20° and 30° showed only the usual diurnal 
changes, while at 40°, 45° and 50° the concentration of the blood in¬ 
creased with the environmental temperature, no initial drop having 
been observed. 


BIBLIOGRAPHY 

(1) Van Slyke: Journ. Biol. Chem., 1917, xxx, 347. 

(2) Van Slyke and Stadie: Journ. Biol. Chem., 1921, xlix, 1. 

(3) MacLean: Biochem. Journ., 1919, xiii, 135. 

(4) Hastings and Hopping: Proc. Soc. Exper. Biol, and Med., 1923, xx, 254. 

(5) Brown: Journ. Amer. Chem. Soc., 1922, xliv, 423. 

(6) Scott and Flinn: Journ. Biol. Chem., 1923, 1, Proc. Soc., 32. 

(7) Cullen: Journ. Biol. Chem., 1922, lii, 501. 

(8) Hastings: Jour. Ind. Eng. Chem., 1921, xiii, 1056. 

(9) Scott and Ford: This Journal, 1923, lxiii, 520. 

(10) Ventilation Report of the New York State commission of Ventilation: 1923, 

p. 51 et seq. 

(11) Rubner: Energiegesetz. 1902, pp. 105-137. 

(12) Henderson and Haggard: Journ. Biol. Chem., 1918, xxxiii, 333. 

(13) Britton: Quart. Journ. Exper. Physiol., 1922, xiii, 55. 

(14) Dreyer, Bazett and Pierce: Lancet, 1920, ii, 588. 

(15) Voit: Zeitschr. f. Biol., 1901, xli, 125. 

(16) Van Slyke: Journ. Biol. Chem., 1921, xlviii, 153. 

(17) Bazett and Haldane: Journ. Physiol., 1921, lv, 125. 

(18) Kahn: Arch. f. Physiol., Supple. 1904, 31. 

(19) Barbour: Physiol. Rev., 1921, i, 295.. 

(20) Bohr, Hasselbach and Ivrogh: Skand. Arch. Physiol., 1907, xvi, 390. 

(21) Hill and Flack: Journ. Physiol., 1909, xxxviii, Proc. lvii and lxi. 

(22) Mayer: Carnegie Pub. no. 252. 

(23) Henderson: Journ. Biol. Chem., 1921, xlvi, 411. 

(24) Henderson: This Journal 1910, xxv, 397. 

(25) Scott and Hastings: Proc. Soc. Exper. Biol, and Med., 1920, xvii, 120. 

(26) Lepine: Rev. Med., 1915, xxxiv, 657. 

(27) Freund and Marchand: Arch. f. Exper. Path. u. Physiol., 1913, Ixxiii, 276. 

(28) Barbour: Proc. Soc. Exper. Biol, and Med., 1921, xviii, 1S4. 

(29) Barbour and Howard : Proc. Soc. Exper. Biol, and Med., 1920, xvii, 148. 


CURRICULUM VITA 


Frederick B. Flinn. Born Reedsville, Penn., September 16, 1876. 

Received elementary education in the Public Schools of Worcester, 
Mass. 

Graduated from Worcester English High School, 1896. 

Received A.B., Johns Hopkins University, 1900. 

Member of American Institute Mining Engineers. Kappa Chapter 
Sigma Xi. 

Publication: Assay of Gold in Copper Bullion, Engineering and 
Mining Journ., March 13, 1909. 

Flotation Apparatus, Chemical and Metallurgical Engineering, Aug. 
15, 1918. 

Lactic Determination, Scott and Flinn, Journ. Biol. Chem., 1922, 
1 proc. Soc. 32. 

Positions: 

Chief Chemist and Assayer Balbach Smelting and Refining Co., 
1900-1902. 

Consulting Metallurgist Compania Metalurgica Mexicana, Tezuit- 
lan Copper Company, Mexican Northern Railroad, 1902-1918. Di¬ 
rector of the Tezuitlan Copper Company, Montezuma Lead Company, 
1914-1919. Vice President and Director Bubble Column Corporation. 
Associate Chemist U.S.P.H.S., 1920-19—. Inventor and Joint pat¬ 
entee with Robt. S. Towne of the pneumatic oil flotation process, 
as well as twelve patents on flotation apparatus. 































